Barlowed laser method help

[johnkirkpatrick]

I want to check if its ok to use the barlowed laser method if the laser is slightly out of collimation itself, I have tried for nearly an hour to collimate the barlow using a peice of wood with some 5" nails in it to rotate the laser on and and have managed to get the laser scribing a small circle from a massive one and its the best i can manage without throwing it out the window.??

[ollypenrice]

I'd give it a try. Even when perfectly collimated a laser sits slightly askew in most focus adapters anyway. A laser is something I use to get close or close enough for most purposes. After that you can't beat a final star test to tickle it up to perfection. Since I need a helper for that I don't often bother and don't really find much practical advantage when I do, though I'm not using the big Newt for imaging or planetary when it really would matter.

Olly

[Chris H]

Yes it will work, the barlow scatters the light from the laser so it makes no difference whether it's slightly out of collimation. It might be worth checking the position of the center spot on the primary if you're going to rely on this method.

[johnkirkpatrick]

Thanks, I dont think it needs done just now as I get pretty sharp images but I tried it and the dohnut seemed to be just a 1 or 2mm out, so will leave it till I can really notice the need to collimate..